Throttle controlled by transmission ratio

ABSTRACT

A throttle control device has a diaphragm actuator controlled by induction vacuum through a solenoid valve to provide increased idle speed in high drive ratio or in reverse and to provide low idle speed in the lower drive ratio with throttle closing at a controlled rate.

United States Patent Danek Mar. 26, 1974 THROTTLE CONTROLLED BY 2,782,025 2/1957 Olson 123/103 E x TRANSMISSION RATIO 2,913,921 11/1959 Gordon 74/873 2,915,914 12/1959 Burnell et a1. 74/873 [75] Inventor: Michael J. Danek, Lamgsburg, 2,976,743 3/1961 Gordon et a1 74/873 Mich. 2,988,873 6/1961 Falberg 92/131 X 3,080,890 3/1963 92/99 [73] Ass1gnee: General Motors Corporation, 3,490,342 H1970 D Mich. 3,556,064 1 1971 Tasuku et a1. 74/860 x 22 F1 d: 14, 1972 I 1 l e June Primary Examiner-Ben3am1n W. Wyche 1 1 pp N01 262,616 Assistant Examiner-J. Reep Attorney, Agent, or FirmArthur N. Krein [52] U.S. Cl 74/860, 74/873, 92/99 51 im. c1 B60k 21/00 [57] ABSTRACT [58] Field of Search... 74/860, 873; 123/108, 103 E; A throttle control device has a diaphragm actuator 92/131, 99 controlled by induction vacuum through a solenoid valve to provide increased idle speed in high drive [56] Refe n e Cited ratio or in reverse and to provide low idle speed in the UNITED STATES PATENTS lower drive ratio with throttle closing at a controlled 2,529,437 11/1950 Weinberger 123/108 x rate 2,762,235 9/1956 Olson et a1 74/873 5 Claims, 2 Drawing Figures THROTTLE CONTROLLED BY TRANSMISSION RATIO This invention relates to a throttle control system and, in particular, to a throttle control system utilizing throttle dash-pot arrangement to control the idle stop position of the throttle in the carburetor of an internal combustion engine.

It is known to provide an ignition timing control system of the type in which a solenoid valve is disposed in the vacuum conduit between the induction passage and a distributor vacuum advance unit, the solenoid valve being energized through a switch when the transmission is in a low drive ratio mode of operation to prevent vacuum advance of the ignition timing whereas, when the transmission is in the high drive ratio mode of operation, the solenoid valve is de-energized to open the vacuum conduit to permit vacuum advance of the ignition timing. Such a control system, known commercially as a Transmission Controlled Spark system has proved effective to maximize fuel economy and engine performance while helping to reduce the emission of undesirable engine exhaust gas constituents.

Another feature adopted on recent engines has been an increase in idle air flow to improve combustion under high speed closed throttle decelerating conditions. This increase has been accomplished by limiting closure of the throttle to what may be termed a fast idle position.

It is therefore an object of this invention to provide a throttle control device for controlling the carburetor idle stop position whereby to reduce deceleration exhaust emissions by allowing the throttle to close from a fast idle position to a slow idle position at a controlled rate to prevent hot stalling.

Another object of this invention is to provide a throttle control device to maintain increased engine idle speed when the engine is driving a transmission at a high drive ratio or in reverse while permitting controlled throttle closing when the engine is driving a transmission in the lower drive ratios.

These and other objects of the invention are attained by means of a spring biased diaphragm actuator controlled by induction vacuum through a solenoid valve to limit throttle closure with transmission in high or reverse drive ratio and vacuum applied and, permitting slow closure of the throttle to its slow idle position with no vacuum applied or in other drive ratios at a closing rate controlled by the flow of air through orifices.

For a better understanding of the invention, as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of a throttle control and ignition timing control arrangement with a solenoid valve disposed in the vacuum conduit between the induction passage and the throttle control and ignition timing control, the solenoid valve being connected through a switch which senses the transmission drive ratio, the actuator of the throttle control unit shownin a retracted position; and,

FIG. 2 is an enlarged sectional view of the throttle control arrangement taken along line 2-2 of FIG. 1, showing the stem of the actuator of this unit fully extended.

Referring now to FIG. 1, an internal combustion engine 10 is illustrated as having a carburetor l1 providing an induction passage 12. A throttle 14 is rotatably disposed on a throttle shaft 15 in the induction passage 12 and is controlled by a throttle lever 16 fixed to the shaft 15. A port 17 opens from the induction passage 12 at a location adjacent the edge of the throttle 14. The port 17 is on the upstream side of the throttle 14 when the throttle is in the closed position as illustrated; when throttle 14 is moved to an open position, its edge traverses port 17 and port 17 then senses the vacuum in the induction passage 12 downstream of throttle 14.

Port 17 is connected through a conduit 18 and a solenoid valve unit 20 via a conduit 21 to a vacuum advance unit 22 mounted on a distributor 23 and through a conduit 24 to the throttle control unit 25 of the invention, the housing of which is suitably, adjustably mounted relative to the carburetor 11 for a purpose which will become apparent.

The solenoid valve unit 20 and the vacuum advance unit 21 are not described or illustrated in detail since they form no part of the invention, and may be of the type illustrated in U.S. Pat. No. 3,584,521 issued June 15, 1971 to Robert S. Tooker and James J. Dawson. The solenoid valve unit 20 has first and second openings 26 and 27 disposed in opposite ends thereof and lateral openings 28 and 30 disposed intermediate the ends. A magnetically responsive valve element 31 having resiliently tipped ends is disposed within the solenoid valve unit and is reciprocal between a pair of valve seats, only one of which is shown, to close either opening 26 or opening 27. A solenoid coil, not shown, is disposed within the solenoid valve unit with one lead 32 of this coil being connected to a voltage source 33 through the engine ignition switch 34. The other lead 35 of the solenoid coil is connected to a switch 36 which opens the circuit when it senses the pressure of the hydraulic fluid used to engage the direct drive clutch in transmission 37 and which closes the circuit to ground in the absence of such pressure. Transmission 37, which is more fully described in the aboveidentified U.S. Pat. No. 3,584,521, and in U.S. Pat. No. 3,321,056 issued May 23, 1967 to Frank J. Winchell et al., includes a plurality of drive ratios which are selectively engagable between an input or driven shaft 38 and an output or drive shaft 40. When a lower drive ratio is engaged between driven shaft 38 and drive shaft 40, the speed of the drive shaft 40 is reduced below the speed of the driven shaft 38 to a greater extent than when the high drive ratio is engaged between driven shaft 38 and drive shaft 40.

With this type transmission, the solenoid valve 20 is energized through the switch 36 when the transmission is in a low drive ratio mode of operation and, when the transmission is in a high drive ratio (direct drive) or in reverse, the solenoid valve 20 is de-energized.

When the solenoid valve unit 20 is energized, the valve element 31 is moved to a position to block the flow through opening 26 and openings 28 and 30 are vented through opening 27 to the atmosphere. If the solenoid valve 20 is de-energized, the valve element 31 is moved to block venting to the atmosphere through opening 27 and opening 26 is placed in communication with openings 28 and 30 to receive a vacuum signal from induction passage 12. Thus, the distributor vacuum advance unit 22 and the throttle control unit 25,

to be described, are vented to the atmosphere in all gears except reverse and direct drive; in reverse and direct drive induction passage 12 pressure is applied to these units.

Referring now to FIG. 2, the throttle control unit 25, of the invention includes a hollow housing formed as a two-piece unit including front and rear housing portions 50 and 51, respectively,'with the outer periphery of a loose diaphragm 52 sandwiched therebetween. An actuator 53 is slidably journalled at one end in the bore 54 in the front housing portion 50 and at its opposite end is journalled in the enlarged bore 55 in one end of a stepped sleeve 56 which extends through the rear housing portion 51 and suitably secured thereto. Stepped sleeve 56 is provided with a passage 57 at one end in communication with bore 55 and at its other end in communication with conduit 24.

As shown, the actuator 53 includes a first shaft portion 58 journalled in the bore 54, this first shaft portion terminating at its free end in a stem 60 positioned to engage the throttle lever 16 fixed to the throttle shaft 15. At its opposite end, the actuator is provided with a tube shaft portion 61 of reduced diameter journalled in the bore 55 in sleeve 56. The actuator is also provided intermediate its end with a stepped annular flange portion 62 providing an annular shoulder 62a joining a radial outward extending shoulder 62b which are adapted to be engaged by the annular bead 52a of the diaphragm. An O-ring 63 positioned in a suitable groove provided for this purpose in the sleeve 56 is positioned to sealingly engage the tube shaft portion 61 of the actuator 53, while a second O-ring 64 positioned in a suitable groove provided for this purpose in the front housing portion 50 sealingly engages the shaft portion 58. A spring 65 positioned within the housing encircles the tube shaft portion 61 with one end abutting an end of the sleeve 56 and its other end abutting the stepped annular flange portion 62 of the actuator 53 to normally bias this actuator toward the left, as seen in FIG. 2, to the extended position shown in this figure.

The diaphragm 52 and the stepped annular flange portion 62 of the actuator 53 form with the front and rear housing portions 50 and 51 front and rear chambers 66 and 67 on opposite sides of the diaphragm, the rear chamber 67 being exposed to atmospheric air pressure through a sized orifice 68 extending through the rear housing portion 51. An axial passage 70 extending from the end of tube shaft portion 61 of the actuator is in communication via one or more radial orifice passages 71 of predetermined size through the wall of the tube shaft portion with the front chamber 66, whereby as will be described in greater detail hereinafter, the front chamber 66 is placed in communication with either the atmosphere or induction pressure through the axial and radial passages 70 and 71, respectively, in the actuator 53.

In operation, the biasing force of spring 65 is such that with equal pressure on opposite sides of the diaphragm 52, the position of the actuator 53, whether extended or retracted, is determined by the position of the throttle lever 16. That is, with the throttle 14 in slow idle position, the spring 65 should be sufficiently weak so as not to overcome the force of the customary throttle return spring 72. If the throttle 14 is moved from slow idle to fast idle position, the spring 65 can help to extend the actuator to follow the movement of the throttle lever whereas, if the throttle is moved from fast idle to slow idle, the throttle lever 16 engages the stemof the actuator to effect movement of it back to its retracted position, this movement being from left to right with reference to FIG. 2. I

However, if the throttle 14 is open, port 17 will b subjected to induction vacuum and then when transmission 37 shifts, for example, to high gear, solenoid valve 20 becomes de-energized so that the vacuum signal can then be transmitted to cause the ignition timing to be advanced and to cause this vacuum signal to be applied to the front chamber 66 of the throttle control unit 25. With differential pressure on opposite sides of the diaphragm 52, the actuator, if not already extended, is rapidly extended and held extended in the position shown in FIG. 2. As long as the vacuum pressure is applied to front chamber 66, the actuator 53 will remain extended to act as a fast idle throttle stop so that upon deceleration, the throttle cannot be initially closed beyond a fast idle position, as determined by the extension of the actuator, as desired. This permits the flow of air to the engine necessary for proper combustion when throttle 14 is initially closed to decelerate the engine. After transmission 37 downshifts to a lower drive ratio, solenoid valve unit 20 is energized and actuator 53 is then permitted to retract, in a manner to be described. Throttle 14 is then permitted to close at a controlled rate to the slow idle position determined by the usual curb idle adjustment screw, not shown. In this position of the throttle, air flow is limited to that required for proper idle operation.

When the throttle is closed, as at idle and during deceleration, the port 17 is subjected to the essentially atmospheric pressure above throttle 14 so that no vacuum signals are provided to either the vacuum advance unit 22 or to the throttle control unit 25.

When transmission 37 is in one of the lower drive ratio modes of operation, switch 36 will cause the solenoid valve 20 to be energized so that both the vacuum advance unit 22 and the throttle control unit 25 are vented to the atmosphere through their connections by conduits 21 and 24, respectively, to the openings 28 and 30, respectively, in communication with opening 27 in the solenoid valve.

With vacuum pressure no longer applied to the front chamber 66 and instead, this chamber now being vented to the atmosphere as described above, the actuator 53 remains extended, in the position shown in FIG. 2, but is not held there. Thus, when the throttle lever 16 contacts it, and is rotated in a clockwise direction to the position shown in FIG. 1, the actuator 53 is slowly allowed to retract to a slow idle or retracted position, with the actuator moving to the right, with reference to FIG. 2, to the slow idle or retracted position, with the rate of return of the actuator to this position being governed by the size of the orifices, that is the orifice 68 in communication with rear chamber 67 and the orifice passages 71 in the actuator 53, the front chamber 66 being slowly vented to the atmosphere through these latter orifice passages 71 via conduit 24 and through the passage 27 in the solenoid valve 20.

Thus, the subject throttle control system provides a fast idle carburetor throttle setting for reverse or high gear closed throttle deceleration with a slow idle carburetor throttle setting for engine operation at idle speed, with the throttle closing to the slow idle position at a controlled rate. Proper combustion is thereby enhanced during high gear closed throttle deceleration.

In the embodiment disclosed, the subject throttle control has been combined with a Transmission Controlled Spark system to assure reduction in emission of undesirable exhaust gas constituents. By combining the throttle control with the Transmission Controlled Spark system, the cost and complexity of the entire system is held to a minimum.

It should be appreciated that in a transmission where the drive ratio is changed manually rather than through the use of hydraulic pressure, switch 36 may be arranged to be operated by the usual transmission shift linkage rather than by hydraulic pressure, as disclosed. Further, it should also be appreciated that the solenoid valve unit may be replaced by other valve mechanisms which are similarly operated in accordance with transmission drive ratios.

What is claimed is:

1. In combination with an internal combustion engine having an induction passage for air flow to the engine; a throttle in said induction passage for controlling air flow therethrough; said throttle having at least fast and slow idle positions; a throttle lever connected to said throttle for controlling the position thereof and having a spring associated therewith to normally bias the throttle lever in a direction to move the throttle toward the slow idle position; an associated transmission with an input connected to said engine and an output connected to a load and with variable ratio drive means driving said output from said input; a throttle control unit for controlling the position of said throttle between said fast idle position and said slow idle position; conduit means including a valve means, controlled by said transmission drive mode, connected at one end to said induction passage upstream of said throttle when said throttle is in a closed position and downstream of said throttle when said throttle is open and at its other end to said throttle control unit for selectively transmitting vacuum signals from said induction passage to said throttle control unit and venting said throttle control unit to the atmosphere as a function of said valve means; said throttle control unit including a housing means; an actuator tube means slidably mounted therein with one end thereof extending from one end of said housing for engagement with said throttle lever and its other end slidably journalled in said other end of said housing means; a diaphragm mounted within said housing means in position to sealingly engage said actuator tube means to form with said housing a first chamber and a second chamber, said actuator being operatively connected to said diaphragm; an orifice in said housing for venting said second chamber to the atmosphere; passage means including at least one orifice passage of predetermined size in said actuator tube means in communication at one end with said first chamber and at its other end with said conduit means; spring means positioned in said second chamber and operatively connected to said actuator to normally bias said actuator and said diaphragm toward an extended position; said valve means including a first passage in communication with said induction passage and a second passage in communication with the atmosphere; and a valve element movable from a first position to permit the transmission of vacuum signals from said induction passage to said first chamber, to a second position to block the flow of vacuum signals from said induction passage and to place said first chamber of said control valve unit in communication with the atmosphere with fluid flow therebetween controlled through said orifice passage at a controlled rate.

2. A throttle control mechanism for an internal combustion engine having an induction passage with a throttle therein for controlling air flow for combustion in the engine, and a throttle lever connected to the throttle, the throttle lever having a spring operatively connected thereto to normally bias the throttle lever in a direction to move the throttle toward a closed position, said engine further having an associated transmission with an input connected to the engine and an output connected to a load and variable ratio drive means driving the output from the input, the variable ratio drive means providing high and low drive ratios and reverse, said throttle control comprising a housing, a diaphragm and an actuator positioned to form with said housing a first chamber and a second chamber, said actuator being operatively connected to and extending through said diaphragm and being slidably journalled in said housing for movement between a retracted position and an extended position corresponding to throttle slow idle and fast idle positions, respectively, in a path followed by the throttle lever in moving the throttle to these positions, respectively, spring means positioned in said second chamber to normally bias said actuator and said diaphragm toward said extended position while permitting retraction of said actuator by said throttle lever while abutting against said actuator and when the pressure in said first chamber and said second chamber are approximately equal, said actuator being adapted to be retained in the extended position when vacuum signals are applied to said first chamber whereby said actuator will act as a movable stop to thereby limit throttle closing to a fast idle position by engagement of throttle lever against said actuator, a conduit connected between said first chamber and said induction passage at a location upstream of said throttle when said throttle is in a closed position and downstream of said throttle when said throttle is open for the transmission of vacuum signals to said first chamber, said conduit including passage means in said actuator terminating in at least one orifice of predetermined size in communication with said first chamber, valve means in said conduit movable between a closed position wherein flow of vacuum signals is prevented and said passage means are placed in communication with the atmosphere and an open position wherein transmission of vacuum signals is permitted, valve operating means connected to said valve means and operatively connected'to said transmission to control movement of said valve means as a function of the drive ratios provided by said transmission.

3. A throttle control for an internal combustion engine having an induction passage with a throttle movable therein by a throttle lever between open, fast idle and slow idle positions to vary engine speed and spring means associated with the throttle lever to normally bias the throttle to the slow idle position, said throttle control comprising an actuator adapted to engage the throttle lever between fast idle and slow idle positions to control its movement therebetween a housing, a flexible diaphragm dividing said housing into atmospheric and vacuum chambers, said actuator being operatively connected to and extending through said diaphragm and reciprocably journalled in opposite ends of said housing with one end of said actuator extending out from said housing for abutting engagement with the throttle lever, sealing means in opposite ends of said housing in sealing engagement with said actuator, means positioned in said atmospheric chamber biasing said diaphragm and said one end of said actuator in a direction toward the throttle fast idle position of the throttle lever, inlet means extending to said vacuum chamber and, means connected to said induction passage to apply engine vacuum to said vacuum chamber to effect movement to and hold said actuator at the fast idle position, said means including transmission controlled means to interrupt engine vacuum to said vacuum chamber and to vent said vacuum chamber to the atmosphere at a controlled rate. i

4. A throttle control according to claim 3 wherein said inlet means includes an inlet in said housing in communication with orifice passage means in said actuator, said orifice passage means including an axial passage in the other end of said actuator from said one end and at least one intersecting radial orifice passage, of predetermined size, in communication with said vacuum chamber.

5. A throttle control according to claim 3 wherein said means connected to said induction passage to apply engine vacuum to said vacuum chamber is connected to said induction passage at a location upstream of said throttle when said throttle is in a closed position and downstream of said throttle when said throttle is in open position whereby engine vacuum is supplied to said vacuum chamber only when said throttle is open and said transmission is operative in a high drive ratio. 

1. In combination with an internal combustion engine having an induction passage for air flow to the engine; a throttle in said induction passage for controlling air flow theretHrough; said throttle having at least fast and slow idle positions; a throttle lever connected to said throttle for controlling the position thereof and having a spring associated therewith to normally bias the throttle lever in a direction to move the throttle toward the slow idle position; an associated transmission with an input connected to said engine and an output connected to a load and with variable ratio drive means driving said output from said input; a throttle control unit for controlling the position of said throttle between said fast idle position and said slow idle position; conduit means including a valve means, controlled by said transmission drive mode, connected at one end to said induction passage upstream of said throttle when said throttle is in a closed position and downstream of said throttle when said throttle is open and at its other end to said throttle control unit for selectively transmitting vacuum signals from said induction passage to said throttle control unit and venting said throttle control unit to the atmosphere as a function of said valve means; said throttle control unit including a housing means; an actuator tube means slidably mounted therein with one end thereof extending from one end of said housing for engagement with said throttle lever and its other end slidably journalled in said other end of said housing means; a diaphragm mounted within said housing means in position to sealingly engage said actuator tube means to form with said housing a first chamber and a second chamber, said actuator being operatively connected to said diaphragm; an orifice in said housing for venting said second chamber to the atmosphere; passage means including at least one orifice passage of predetermined size in said actuator tube means in communication at one end with said first chamber and at its other end with said conduit means; spring means positioned in said second chamber and operatively connected to said actuator to normally bias said actuator and said diaphragm toward an extended position; said valve means including a first passage in communication with said induction passage and a second passage in communication with the atmosphere; and a valve element movable from a first position to permit the transmission of vacuum signals from said induction passage to said first chamber, to a second position to block the flow of vacuum signals from said induction passage and to place said first chamber of said control valve unit in communication with the atmosphere with fluid flow therebetween controlled through said orifice passage at a controlled rate.
 2. A throttle control mechanism for an internal combustion engine having an induction passage with a throttle therein for controlling air flow for combustion in the engine, and a throttle lever connected to the throttle, the throttle lever having a spring operatively connected thereto to normally bias the throttle lever in a direction to move the throttle toward a closed position, said engine further having an associated transmission with an input connected to the engine and an output connected to a load and variable ratio drive means driving the output from the input, the variable ratio drive means providing high and low drive ratios and reverse, said throttle control comprising a housing, a diaphragm and an actuator positioned to form with said housing a first chamber and a second chamber, said actuator being operatively connected to and extending through said diaphragm and being slidably journalled in said housing for movement between a retracted position and an extended position corresponding to throttle slow idle and fast idle positions, respectively, in a path followed by the throttle lever in moving the throttle to these positions, respectively, spring means positioned in said second chamber to normally bias said actuator and said diaphragm toward said extended position while permitting retraction of said actuator by said throttle lever while abutting against said actuator and when the pressure in saiD first chamber and said second chamber are approximately equal, said actuator being adapted to be retained in the extended position when vacuum signals are applied to said first chamber whereby said actuator will act as a movable stop to thereby limit throttle closing to a fast idle position by engagement of throttle lever against said actuator, a conduit connected between said first chamber and said induction passage at a location upstream of said throttle when said throttle is in a closed position and downstream of said throttle when said throttle is open for the transmission of vacuum signals to said first chamber, said conduit including passage means in said actuator terminating in at least one orifice of predetermined size in communication with said first chamber, valve means in said conduit movable between a closed position wherein flow of vacuum signals is prevented and said passage means are placed in communication with the atmosphere and an open position wherein transmission of vacuum signals is permitted, valve operating means connected to said valve means and operatively connected to said transmission to control movement of said valve means as a function of the drive ratios provided by said transmission.
 3. A throttle control for an internal combustion engine having an induction passage with a throttle movable therein by a throttle lever between open, fast idle and slow idle positions to vary engine speed and spring means associated with the throttle lever to normally bias the throttle to the slow idle position, said throttle control comprising an actuator adapted to engage the throttle lever between fast idle and slow idle positions to control its movement therebetween a housing, a flexible diaphragm dividing said housing into atmospheric and vacuum chambers, said actuator being operatively connected to and extending through said diaphragm and reciprocably journalled in opposite ends of said housing with one end of said actuator extending out from said housing for abutting engagement with the throttle lever, sealing means in opposite ends of said housing in sealing engagement with said actuator, means positioned in said atmospheric chamber biasing said diaphragm and said one end of said actuator in a direction toward the throttle fast idle position of the throttle lever, inlet means extending to said vacuum chamber and, means connected to said induction passage to apply engine vacuum to said vacuum chamber to effect movement to and hold said actuator at the fast idle position, said means including transmission controlled means to interrupt engine vacuum to said vacuum chamber and to vent said vacuum chamber to the atmosphere at a controlled rate.
 4. A throttle control according to claim 3 wherein said inlet means includes an inlet in said housing in communication with orifice passage means in said actuator, said orifice passage means including an axial passage in the other end of said actuator from said one end and at least one intersecting radial orifice passage, of predetermined size, in communication with said vacuum chamber.
 5. A throttle control according to claim 3 wherein said means connected to said induction passage to apply engine vacuum to said vacuum chamber is connected to said induction passage at a location upstream of said throttle when said throttle is in a closed position and downstream of said throttle when said throttle is in open position whereby engine vacuum is supplied to said vacuum chamber only when said throttle is open and said transmission is operative in a high drive ratio. 